Cause

By design, in case of APS 1.2, any change to subscription resources triggers a full reconfiguration of DNS records: APS controller fetches the list of records the subscription APS 1.2 application(s) owns and re-adds them to the system. No check is done if the records currently exist or not. This leads to a possible error, when there are same records added manually under the account, since APS controller changes only system records.

Resolution

Remove the manually added DNS records from the affected subscription and re-try the operation. Add the records again, if needed.